The present invention relates generally to an airfoil, such as a wind turbine, mounted on a wind turbine tower. More particularly, the present invention relates to a wind turbine that is easily raised atop and lowered from a wind turbine tower.
In the past, typical wind turbine technology placed the turbine shaft, gearbox, and electrical generator in a wind turbine housing at the top of a tower. This arrangement requires a tall crane to lift the wind turbine housing and place it atop the tower during initial construction. The crane is also required to lower the housing whenever major maintenance, such as blade or gearbox replacement, is required, or during periods of inclement weather. Having to bring in a crane to lower the housing from the tower is not only inefficient, but the associated wind turbine down time is very costly as well. Because of the difficulties associated with lowering the wind turbine housing from the tower, one solution has been to design wind turbines that can withstand severe loads such as those caused by hurricanes. This has the effect of increasing the weight of the components and the overall cost of the wind turbine assembly. In addition, the increased weight of the components makes it more difficult to perform maintenance at the top of the tower.
Thus, there exists a need for a wind turbine assembly that includes a driving device for raising and lowering a wind turbine between an upper end and a lower end of a wind turbine tower, as well as a structure for protecting the wind turbine while in a lowered position.